//--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
// Copyright 2012 Microsoft Corporation. All Rights Reserved
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.   
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
//--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

namespace Preflight.Security
{
    using System.Globalization;
    using System.Security.Cryptography;
    using System.Security.Cryptography.X509Certificates;

    internal class CertificateFactory : ICertificateFactory
    {
        private static ICertificateFactory instance = new CertificateFactory();

        private CertificateFactory()
        {
        }

        public static ICertificateFactory Instance
        {
            get
            {
                if (instance == null)
                {
                    instance = new CertificateFactory();
                }

                return instance;
            }

            internal set
            {
                instance = value;
            }
        }

        public X509Certificate2 GetCertificate(CertificateLocation location)
        {
            var certificateStore = new X509Store(location.StoreName, location.StoreLocation);
            certificateStore.Open(OpenFlags.ReadOnly);
            try
            {
                foreach (var certificate in certificateStore.Certificates)
                {
                    if (string.Compare(certificate.Thumbprint, location.Thumbprint, true, CultureInfo.InvariantCulture) == 0)
                    {
                        return certificate;
                    }

                    certificate.Reset();
                }
            }
            finally
            {
                certificateStore.Close();
            }

            throw new CryptographicException("Could not find certificate: " + location);
        }
    }
}
